1. Field of the Invention
The present invention relates to a plasma processing apparatus of the batch type for performing a plasma process, such as a film formation process or etching process using plasma, on target substrates, such as semiconductor wafers, and particularly to a technique utilized in the semiconductor process field. The term “semiconductor process” used herein includes various kinds of processes which are performed to manufacture a semiconductor device or a structure having wiring layers, electrodes, and the like to be connected to a semiconductor device, on a target substrate, such as a semiconductor wafer or a glass substrate used for an FPD (Flat Panel Display), e.g., an LCD (Liquid Crystal Display), by forming semiconductor layers, insulating layers, and conductive layers in predetermined patterns on the target substrate.
2. Description of the Related Art
In manufacturing integrated circuits, a semiconductor wafer, such as a silicon wafer is subjected to various processes, such as film formation, etching, oxidation, diffusion, reformation, and natural oxide film removal. As apparatuses for performing the processes described above on semiconductor wafers, there is known a processing apparatus of the single-substrate type configured to process semiconductor wafers one by one, and a processing apparatus of the batch type configured to process a plurality of semiconductor wafers all together.
In recent years, owing to the demands of increased miniaturization and integration of semiconductor integrated circuits, it is required to process wafers at a lower temperature. This is intended to prevent the profile of doping impurities from changing, to prevent inter-level insulating films, such as low dielectric constant insulating films, from degrading their film quality, and/or to accept the limit of the heat-resistance temperature of underlying laminated films. In order to reply to such a demand, plasma processing apparatuses are often used to perform various processes, such as those described above, at a lower temperature while utilizing plasma assistance.
Jpn. Pat. Appln. KOKAI Publication No. 2004-285469 (Patent Document 1) and Jpn. Pat. Appln. KOKAI Publication No. 2005-64017 (Patent Document 2) disclose examples of the plasma processing apparatuses of the single-substrate type. According to the processing apparatuses disclosed in these documents, for example, an RF (radio frequency) power is applied across parallel-plate electrodes to generate plasma. This plasma is used to activate a process gas, so that a predetermined process, such as film formation or etching, can be performed at a relatively low temperature.
Jpn. Pat. Appln. KOKAI Publication No. 2-159027 (Patent Document 3) and Jpn. Pat. Appln. KOKAI Publication No. 3-224222 (Patent Document 4) disclose examples of the plasma processing apparatuses of the batch type. According to the processing apparatuses disclosed in these documents, a vertical process container configured to array wafers at regular intervals is used. The process container is surrounded by a plurality of electrodes arrayed in an annular direction, to which an RF power is applied to generate plasma.
US 2006/0205231 A1 (Patent Document 5) discloses a plasma processing apparatus including a vertical process container made of quartz and a plasma generation mechanism disposed on one side of the process container along its longitudinal direction. A process gas is activated by plasma generated by the plasma generation mechanism and is horizontally supplied into the process container, so that a predetermined plasma process, such as film formation, is performed on the surface of semiconductor wafers.